function ativarCarrossel()
{
    var handlePrevButtonState = function(type, args) {
              
        var enabling = args[0];
        var leftImage = args[1];
        if(enabling) {
          leftImage.src = 'images/left-enabled.gif';    
        } else {
          leftImage.src = 'images/left-disabled.gif';    
        }    
    };

    var handleNextButtonState = function(type, args) {
    
        var enabling = args[0];
        var rightImage = args[1];
        
        if(enabling) {
            rightImage.src = 'images/right-enabled.gif';
        } else {
            rightImage.src = 'images/right-disabled.gif';
        }
        
    };
    
    var carousel;

    carousel = new YAHOO.extension.Carousel('mycarousel', 
        {
            numVisible:        2,
            animationSpeed:    0.15,
            scrollInc:         2,
            navMargin:         30,
            prevElement:     'prev-arrow',
            nextElement:     'next-arrow',
            size:              6,
            prevButtonStateHandler:   handlePrevButtonState,
            nextButtonStateHandler:   handleNextButtonState
        }
    );    
    YAHOO.util.Event.addListener(window, 'load', carousel);
}